1. Field of the Invention
This invention relates to a circuit for selecting internal integrated circuit chip functions and more particularly to a circuit which can select the functional operation of the integrated circuit chip without external pull-up resistors.
2. Description of Related Art
This invention enables the design of an integrated circuit chip having multiple configurations which may be selected without the use of external pull-up resistors and without the use of additional input/output pins in the integrated circuit packaging. Standardized packaging typically has a fixed number of input/output pins. For instance an 8 pin package would typically have only a single power supply voltage pin which would likely have only limited space for bonding. However although there would likely only be a single ground pin there would be, conversely a substantial amount of space on grounded portions of the lead frame used in the package to tack terminal pads of the integrated circuit to ground as desired.
Bootstrapping resistors such as pull-up or pull-down resistors while being useful solution to the problem cause complications because of size limitations and power consumption. Both of these complications are undesirable because of the small size of integrated circuitry and because of the desirability of reducing power consumption to an absolute minimum required for battery power of the circuitry.
We have found that wire bond bootstrapping of an integrated circuit inside a molded package at the time of packaging can be used to enable or disable modes of operation of the integrated circuit.